Changing a playback speed for video presentation recorded in a modified film format

Abstract

The invention includes a system and method 300 for changing a playback speed of a selected video segment having repeat fields. To achieve fast motion play a selected video segment can be modified to delete repeat fields 340 . Further pictures can be deleted as required 360 to achieve a desired playback speed. To achieve slow motion play, a selected video segment can be modified by encoding repeat fields into conventional field pictures. Further pictures can be added as required to achieve a desired playback speed 330 . Further, a repeat first field flag in the picture header of the picture containing the repeat field can be set to zero 325 . Furthermore, a GOP structure of the modified video segment can be reencoded into a conventional 365 or a desired 367 GOP structure. Additionally, the modified video segment can be recorded exclusively on a desired portion of a storage medium 370.

We claim:  
     
       1. In a rewritable storage medium, a method for changing a playback speed of a selected video segment having repeat fields comprising the steps of: 
       selecting the selected video segment, wherein the selected video segment has repeat fields; and,  
       modifying said selected video segment by removing repeat fields to achieve fast motion play.  
     
     
       2. The method according to  claim 1 , wherein said removing repeat fields to achieve fast motion play comprises the step of setting a repeat first field flag located in a picture header to zero. 
     
     
       3. The method according to  claim 1 , further comprising the step of removing pictures from said selected video segment to achieve a desired playback speed. 
     
     
       4. The method according to  claim 1 , further comprising the step of reencoding said selected video segment into a desired GOP structure after modifying said selected video segment. 
     
     
       5. The method according to  claim 1 , further comprising the step of recording said modified video segment exclusively on a desired portion of a storage medium. 
     
     
       6. In a rewritable storage medium, a method for changing a playback speed of a selected video segment comprising the steps of: 
       selecting the selected video segment, wherein the selected video segment has repeat fields; and,  
       encoding said repeat fields into conventional field pictures to change the playback speed of the video segment.  
     
     
       7. The method according to  claim 6 , further comprising the step of setting a repeat first field flag located in a picture header to zero. 
     
     
       8. The method according to  claim 6 , further comprising the step of adding dummy pictures to said selected video segment to achieve a desired playback speed. 
     
     
       9. The method according to  claim 6 , further comprising the step of reencoding said selected video segment into a desired GOP structure after modifying said selected video segment. 
     
     
       10. The method according to  claim 6 , further comprising the step of recording said modified video segment exclusively on a desired portion of a storage medium from which said video segment was read. 
     
     
       11. In a rewritable storage medium, a method for modifying a selected video segment having repeat fields comprising the steps of: 
       replacing said repeat fields with dummy pictures; and  
       setting a repeat first field flag located in a picture header to zero.  
     
     
       12. The method according to  claim 11 , further comprising the step of adding dummy pictures to said selected video segment to achieve a desired playback speed. 
     
     
       13. The method according to  claim 11 , further comprising the step of reencoding said selected video segment into a desired GOP structure after modifying said selected video segment. 
     
     
       14. The method according to  claim 11 , further comprising the step of recording said modified video segment exclusively on a desired portion of a storage medium. 
     
     
       15. A system for changing the playback speed of a selected video segment having repeat fields, comprising: 
       storage medium reading circuitry for selectively reading a video segment which has been recorded on a first portion of a rewritable storage medium;  
       a video processor for modifying said selected video segment for a changed playback speed; and  
       video recorder circuitry for recording said modified video segment exclusively on said first portion of said storage medium.  
     
     
       16. The system according to  claim 15 , wherein said video processor modifies said selected video segment by removing said repeat fields to achieve fast motion play. 
     
     
       17. The system according to  claim 15 , wherein said video processor modifies said selected video segment by encoding said repeat fields into conventional field pictures. 
     
     
       18. The system according to  claim 15 , wherein said video processor sets a repeat first field flag located in a video header to zero after modifying said selected video segment. 
     
     
       19. The system according to  claim 15 , wherein said video processor deletes a plurality of non-video packs in said selected video segment to reduce an amount of data contained in said modified video segment. 
     
     
       20. The system according to  claim 15 , wherein said video processor reduces a resolution of at least one frame contained in said modified video segment. 
     
     
       21. The system according to  claim 15 , wherein said video processor lowers a bit rate of said modified video segment during a recording step. 
     
     
       22. The system according to  claim 15 , wherein said video processor inserts into said selected video segment at least one dummy picture. 
     
     
       23. The system according to  claim 15 , wherein said video processor deletes from said selected video segment at least one picture. 
     
     
       24. In a rewritable storage medium, a method for changing a playback speed of a selected video segment comprising the steps of: 
       selecting the selected video segment, wherein the selected video segment has repeat fields;  
       encoding said repeat fields into conventional field pictures; and,  
       setting a repeat first field flag located in a picture header to zero.  
     
     
       25. A system for changing the playback speed of a selected video segment having repeat fields, comprising: 
       storage medium reading circuitry for selectively reading a video segment which has been recorded on a portion of a rewritable storage medium;  
       a video processor for modifying said selected video segment for a changed playback speed; and,  
       video recorder circuitry for recording said modified video segment exclusively on a portion of said storage medium;  
       wherein said video processor modifies said selected video segment by removing said repeat fields to achieve fast motion play.  
     
     
       26. A system for changing the playback speed of a selected video segment having repeat fields, comprising: 
       storage medium reading circuitry for selectively reading a video segment which has been recorded on a portion of a rewritable storage medium;  
       a video processor for modifying said selected video segment for a changed playback speed; and,  
       video recorder circuitry for recording said modified video segment exclusively on a portion of said storage medium;  
       wherein said video processor sets a repeat first field flag located in a video header to zero after modifying said selected video segment.  
     
     
       27. In a rewritable storage medium, a method for changing a playback speed of a selected video segment comprising the steps of: 
       reading the selected video segment from a first storage location, wherein the selected video segment has repeat fields;  
       encoding said repeat fields into conventional field pictures to change the playback speed of the video segment; and,  
       recording said modified video segment exclusively on a second storage location, said second storage location baying a physical space not larger than said first storage location.